The present invention relates to a camera, especially to a camera comprising plural built-in microcomputers which communicate with each other to execute a series of control steps.
In a camera comprising a main body section and a rear cover section, it is known to provide plural microcomputers disposed respectively in the main body section and the rear cover section. The microcomputer in the main body may control photography, film advance and flashing, while the microcomputer in the rear cover may control the other supplemental functions.
Furthermore, in the case of a camera having a date module for recording the date and other data on a loaded film, it is preferable to provide a microcomputer in the rear cover for controlling the date module, because, although a battery for circuitry in the camera main body needs to supply relatively high power and thus must be changed frequently, the date module draws only as much electric power as a wristwatch, and so the power supply for the microcomputer for the date module will last for four to five years. As the result, it becomes possible to store data in the date module for a long time.
It is also preferable to dispose various kinds of mode selection switches including a film rewinding switch integrally in the rear cover, because this construction facilitates the operation of the switches and lowers the cost of the camera. Meanwhile, a film rewinding switch is adapted to rewind the film before the loaded film has entirely been exposed if the rear cover must be opened to repair the camera, or to change the battery, for instance.
However, because the condition of the battery for the date module cannot be monitored, there is a danger that the battery has discharged suddenly during photography. In such a case, if the film rewinding switch and a microcomputer for controlling the film rewinding switch are disposed in the rear cover and are supplied by the battery common to the date module, the film rewinding switch cannot operate. This problem will occur if any trouble occurs in the microcomputer for the manual film rewinding switch, such as a breakdown of the connection between the microcomputer and a battery, or a fault in the microcomputer itself.